Detection of lipid peroxidation in lung and in bronchoalveolar lavage cells and fluid

Inhalation of toxic materials such as asbestos, silica, 100% oxygen, ozone, or nitrogen dioxide may lead to an increased production of reactive oxygen metabolites which may initiate lipid peroxidation. Measurement of lipid peroxidation in cells and fluid obtained by bronchoalveolar lavage (BAL), as well as in lung tissue, may aid in monitoring the development and extent of pulmonary damage after inhalation of a toxic substance. In this study, we employed a sensitive assay for detection of malondialdehyde (MDA), a breakdown product of lipid peroxidation. By separation of the adduct with thiobarbituric acid, using a reverse phase high pressure liquid chromatographic technique, we accurately and sensitively measured the content of MDA in BAL cells, lavage fluid, and lavaged lung tissue homogenates of rats. The amounts of sample required for detection of MDA were small enough possibly to be applied to use with human specimens; in addition, recovery of added MDA was acceptable with all types of samples. Inclusion of a metal chelator in the preparation of samples appeared necessary to prevent metal-catalyzed propagation of lipid peroxidation during the assay. Overall, the method described here using samples from rats may be applicable to detecting lipid peroxidation in BAL samples from humans.